723. Immunogenicity and Duration of Protection Among Hemodialysis Patients After Primary or Revaccination Series of Hepatitis B Vaccine: Implications for Defining Vaccine-Induced Immunity
Session: Poster Abstract Session: Vaccine Studies, Adjuvants, and Discovery
Friday, October 21, 2011
Room: Poster Hall B1
Background: Hepatitis B vaccination is recommended for patients on hemodialysis, however, seroprotection after a primary vaccine series is suboptimum. Limited data are available on the effect of revaccination of non-responders and on persistence of immunity in this population with currently approved regimens.

Methods: Hepatitis B vaccine (40 µg/dose) was given to 77 susceptible patients on hemodialysis (0, 1, and 6 month schedule). Levels of hepatitis B surface antibody (anti-HBs) were tested >28 days after the third dose was administered, and non-responders revaccinated with an additional 3-dose series. Vaccine responders (anti-HBs ≥10 mIU/mL) were re-tested every 6 months and booster doses given as needed. Kaplan-Meier survival curve was used to estimate the probability of maintaining protective antibody level.  Cox-proportional hazards model was used to assess the association between time to loss of protective antibody levels and certain explanatory variables.

Results: Overall vaccine-induced response was 79.2% (95% CI 68.2%, 87.3%). Among weak responders, protective antibody levels persisted in 44% for 12 months post-vaccination; whereas among strong responders (anti-HBs level ≥100 mIU/mL), protective antibody levels persisted in 92% for 12 months, and 68% for 24 months post-vaccination. A weak post-vaccination response (anti-HBs level 10.0-99.9 mIU/mL) increased the risk of losing protective antibody levels (adjusted hazard ratio, 9.7; 95% confidence interval, 3.5-28.5; p<0.0001).

Conclusion: Revaccinating patients undergoing hemodialysis who do not respond to a primary vaccine series substantially increases the pool of protected patients. The threshold for defining hepatitis B vaccine-induced immunity should be revisited in this patient population to maximize the duration of protection.

Subject Category: I. Adult and Pediatric Vaccines

Sandra Chaves, MD, MSc1, Danni Daniels, MS1, Brian Cooper, MD2, Susan Malo-Schlegel, RN CIC2, Susan MacArthur, RN CIC CPHQ MPH3, John Kobetitsch, R.N. J.D.2, Aimee McDanial, MSN RN2, John D'Avella, MD FASN2 and Miriam J Alter, PhD4, (1)Centers for Disease Control and Prevention, Atlanta, GA, (2)Hartford Hospital, Hartford, CT, (3)Connecticut Childrens Medical Center, Hartford, CT, (4)University of Texas Medical Branch, Galveston, TX


S. Chaves, None

D. Daniels, None

B. Cooper, None

S. Malo-Schlegel, None

S. MacArthur, None

J. Kobetitsch, None

A. McDanial, None

J. D'Avella, None

M. J. Alter, None

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